1. Field of the Invention
The present invention relates generally to safety systems for vehicles to enhance occupant protection during a crash. The invention specifically relates to activation of crash safety systems employing kinetic energy generated by an inertial mass constrained for movement within the vehicle and released by impact forces.
2. Description of the Prior Art
Crash safety in automobiles and other highway vehicles is a continuing area of concern for vehicle designers. Present vehicles employ a wide array of safety devices including seat belts, shoulder harnesses, air bags, and energy-absorbing collapsible structures.
Seat belt restraining systems including inertia reels and other devices for locking or tensioning the seat belt during a crash. Present designs employ position actuators, propellant driven turbines, or similar systems actuated by acceleration sensors to reduce slack or impose tension on the seat belt shoulder harness system. In some configurations, belt webbing is played out at a controlled force through tensioning systems to decelerate the occupant under conditions of high crash loads. These systems require highly reliable sensing systems to detect crash accelerations and require separate energy sources such as propellant charges or the like for operation.
Similarly, air bags are being employed in numerous vehicles for added occupant safety. Present air bag systems require sensors for detecting crash accelerations and propellant cartridges or other stored energy systems to inflate the bag upon actuation.
To obtain efficiency from common control and power source the subsystems of conventionally powered vehicles may be grouped and centrally located on a pallet within the vehicle. The subsystems such as hydraulic pumps and actuators for power steering, air conditioning systems, electronics such as stereo and mobile telephones which require electrical or supplemental power not driven directly from the drive train of the vehicle may be aggregated in such a system.
Additionally, alternatively powered vehicles are presently being designed and entering the consumer arena based on demand for clean, non polluting, non petroleum energy based transportation. Electric vehicles are becoming a viable alternative to gasoline or other petroleum based internal combustion engine vehicles. Vehicles employing hybrid systems of partial battery and partial internal combustion, fuel cell or other energy systems are also undergoing research and development.
Each of these alternative systems employs, as a portion of its system, components which are heavy masses that impart little mechanical torque or other forces requiring rigid constraint within the vehicle. It is desireable to employ the inertial mass in these alternative systems as an enhancement in the activation and operation of safety systems within the vehicle to reduce the cost and complexity while increasing the reliability of those systems.